Supplement–drug interactions
Supplements That Interact with Blood thinners (warfarin, DOACs)
23 supplements in NutriDex have a known or theoretical interaction with blood thinners (warfarin, doacs), including 1 best avoided entirely. Grouped by severity below; each links to its full evidence, dosing & mechanism. This is educational and not exhaustive — always tell your doctor or pharmacist about every supplement you take before combining it with medication.
Avoid — do not combine 1
St. John's Wort lowers warfarin levels, weakening anticoagulation and raising clot risk.
Caution — use only with medical guidance 17
Bromelain may increase bleeding risk when combined with blood thinners.
Chaga may add to bleeding risk when combined with blood thinners.
Chamomile contains coumarins and has been reported to interact with warfarin, raising bleeding risk.
Dong quai may increase bleeding and raise INR when combined with warfarin.
Feverfew may slow blood clotting and increase bleeding risk with blood thinners; stop before surgery.
Horse chestnut may increase bleeding risk when combined with blood thinners.
Nattokinase can add to blood thinners and raise bleeding risk; combined use has been linked to hemorrhage.
Panax ginseng may reduce warfarin's effect (lower INR), potentially raising clot risk.
Policosanol may prolong bleeding time when combined with warfarin.
High-dose quercetin may interfere with warfarin and add antiplatelet effects; monitor INR and bleeding.
Red clover contains coumarins and may increase bleeding risk when combined with blood thinners.
Serrapeptase may add to bleeding risk when taken with blood thinners.
Nettle is high in vitamin K and may REDUCE warfarin's effect; keep intake consistent and monitor INR.
High-dose vitamin E can increase bleeding and raise INR with warfarin or antiplatelets.
Vitamin K1 REDUCES warfarin's effect (lowers INR); inconsistent intake destabilizes anticoagulation.
Vitamin K2 REDUCES warfarin's blood-thinning effect (lowers INR); fluctuating intake risks clots.
White willow's salicylates may add to blood thinners and raise bleeding risk.
Monitor — watch for effects 5
High-dose algae oil may slightly add to bleeding risk alongside blood thinners.
High-dose cod liver oil may slightly add to bleeding risk alongside blood thinners.
High-dose flaxseed or flaxseed oil may slightly add to bleeding risk alongside blood thinners.
High-dose krill oil may slightly add to bleeding risk alongside blood thinners; watch for easy bruising.
High-dose fish oil may slightly add to bleeding risk alongside blood thinners.
Each supplement links to its full evidence, dosing, mechanism & citations. See also all medication interaction guides →